HELP!!!

I have a uk wagon which has a BAD oil leak from the gearbox. Seems like the input shaft oil seal(i hope) coz the gearbox is still selecting gears etc ok. Was coming back from a long journey and smoke poured from behind us.Looked underneath and oil is spewing from the gearbox onto the exhaust. Carried on the journey, had it in fifth gear and needed to overtake and the clutch started the slip.Must have spat oil on the clutch.oh FFS. Did have problems with the clutch before but it seems to pass so have got a clutch ready for it just wondering how difficult it is to change the oil seal in the front of the gearbox or whether better off changing the box.And if i changed it wot box would be the best to go for.

spec is a uk waqgon with scoobyecu,frontmount intercooler,induction kit,aftermarket actuator and td05 turbo(standard on uk wagons 95/6)
with full decat
Any help and advice would be appreciated

THX Gav

 

Definitely input shaft oil seal, happened to me last year on 03STi, oil everywhere and car still stinks when hot. Gearbox has to come off to access oil seal. AFAIK the seal is accessed from inside the bell housing and box does not need to be dismantled. Clutch driven plate will be scrap as will be oil soaked.